The present invention broadly relates to chuck structures for winding machines and, more specifically, pertains to a new and improved construction of a chuck structure for use in winding machines and particularly, but not exclusively, for use in high speed winding machines for the take-up of synthetic plastics filament. In this context, "high-speed" refers to speeds in excess of 3000 m/min. and especially to speeds in excess of 5000 m/min.
Generally speaking, the present invention relates to a new and improved construction of a chuck for cantilever-mounting in a winder for rotation about a longitudinal chuck axis, and to elements and devices for use in such chucks. When used hereinafter in this specification, the word "chuck" relates to a chuck as defined in this paragraph.
In other words, one aspect of the present invention relates to a chuck having an axis of rotation, while a second aspect relates to a bobbin tube-engaging element for mounting in a chuck for movement radially thereof between an operating position engaging the interior of a bobbin tube and an inoperative or idle position for enabling release of the bobbin tube.
Filament winders designed for the take-up of synthetic plastics filament can be classified into two types those intended for taking-up relatively coarse (heavy denier or heavy titre) filaments and those intended for taking-up relatively fine filaments. The coarser filaments are normally used for industrial purposes, e.g. in tire cord and in carpet yarn; the finer filaments are generally used for textile purposes. The coarser filaments have a much greater rupture or breaking strength than the finer filaments. The difference in the breaking strength of the two filament types has in the past exerted a substantial influence on the design of the chuck or chucking device (also referred to as "spindle" or "mandrel") used in continuous or wasteless winders. Examples of such winders can be found in European Published Patent Application No. 73,930 and U.S. Pat. Nos. 4,298,171, granted Nov. 3, 1981; 4,014,476, granted Mar. 29, 1977; and 4,186,890, granted Feb. 5, 1980. Examples of chucks for such winders can be found in U.S. Pat. Nos. 4,336,912, granted June 29, 1982; and 4,460,133, granted July 17, 1984.
As will be seen from the prior patents referred to above, a continuous winder comprises at least two chucks, one of which is held on standby, i.e. in readiness, while a package is being formed on the other chuck. When the package is complete, a chuck changeover operation is effected in the course of which the thread being wound is transferred to the "incoming" chuck while the "outgoing" chuck is moved to a doffing position. In the doffing position, the completed package can be removed from the outgoing chuck and replaced by a fresh bobbin tube, ready for another changeover as an incoming chuck when the current package winding operation is completed.
In continuous winders it is necessary to catch the thread on the incoming chuck and to sever the thread between the incoming and outgoing chucks. For relatively fine filaments, it is possible to provide catching slots in the bobbin tubes and to rely upon tearing or rupture of the filament between the incoming and outgoing chucks after catching the filament on the incoming chuck. For relatively coarse filaments, however, it has heretofore been necessary to incorporate catching and severing devices in the chuck structures, for example as described in U.S. Pat. Nos. 4,106,711, granted Aug. 15, 1978 and 4,477,034, granted Oct. 16, 1984; in the aforementioned U.S. Pat. Nos. 4,336,912 and 4,460,133; and in European Pat. No. 470.
Chucks designed for use with relatively fine filaments generally include a tube functioning simultaneously as an outer casing or shell of the chuck and as the major structural element thereof, providing the cantilever-mounted chuck with both strength and rigidity n operation. This tube is generally secured at one end to a hollow stub shaft cooperating with bearings in the cantilever mounting for the chuck in the winder. However, the join or connection between the stub shaft and the tube inevitably reduces the space available within the end portion of the tube and production of an adequate join or connection can therefore give rise to problems. The space within the tube is always important for the design of the bobbin tube clamping and locating systems accommodated within the tube in use.
A different chuck design is generally used for relatively coarse filaments. In this alternative design, the major structural element providing strength and rigidity to the chuck is a longitudinal "core" tube. The thread-catching and severing structures and the bobbin tube clamping systems are carried on the exterior of this core tube, and the assembly is partially enclosed in a surrounding casing or shell. The latter has, however, no structural function, and it is discontinuous to enable access of the thread to the catching and severing structures.
For given materials forming the load-bearing tube, and for a given proportion of the chuck cross-section allocated to that tube, a chuck of the second type will be neither as strong nor as rigid as an equivalent chuck of the first type. Furthermore, the externally mounted elements are not as securely retained as corresponding elements in a chuck of the first type.
The present invention provides a combination of features which, at least in certain operating circumstances, presents significant advantages over both of the types referred to above.